[PATCH 02/11] mfd: flexcard: add flexcard core device

[Holger Dengler <dengler@linutronix.de>]

From: Benedikt Spranger <b.spranger@linutronix.de>

The Flexcard PCI BAR0 contain registers for configuration but also
for informational purpose like error counter, statistical information
and some timestamps. The read-only mmap of the misc device offers the
userspace a fast access to these registers.

Signed-off-by: Holger Dengler <dengler@linutronix.de>
Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
cc: Samuel Ortiz <sameo@linux.intel.com>
cc: Lee Jones <lee.jones@linaro.org>
---
 drivers/mfd/flexcard/core.c  | 107 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/mfd/flexcard.h |   6 +++
 include/uapi/linux/Kbuild    |   1 +
 3 files changed, 112 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/flexcard/core.c b/drivers/mfd/flexcard/core.c
index 99df3d5..1e7fb0f 100644
--- a/drivers/mfd/flexcard/core.c
+++ b/drivers/mfd/flexcard/core.c
@@ -14,11 +14,16 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/flexcard.h>
+#include <linux/fs.h>
+#include <linux/kref.h>
+#include <linux/miscdevice.h>
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/mfd/core.h>
 #include <linux/mfd/flexcard.h>
 
+static DEFINE_IDA(flexcard_ida);
+
 static const char drv_name[] = "flexcard";
 
 static int flexcard_tiny_can(struct flexcard_device *priv,
@@ -104,23 +109,106 @@ static int flexcard_tiny_probe(struct flexcard_device *priv)
 	return mfd_add_devices(&pdev->dev, 0, priv->cells, nr, NULL, 0, NULL);
 }
 
+static int flexcard_misc_open(struct inode *inode, struct file *filp)
+{
+	struct flexcard_device *priv =
+		container_of(filp->private_data, struct flexcard_device, dev);
+	int ret;
+
+	filp->private_data = priv;
+	ret = nonseekable_open(inode, filp);
+	if (ret) {
+		dev_err(&priv->pdev->dev, "unable to open file: %d\n", ret);
+		return ret;
+	}
+
+	kref_get(&priv->ref);
+	return 0;
+}
+
+static void flexcard_dev_release(struct kref *ref)
+{
+	struct flexcard_device *priv =
+		container_of(ref, struct flexcard_device, ref);
+
+	kfree(priv);
+	dev_info(&priv->pdev->dev, "misc device release");
+}
+
+static int flexcard_misc_release(struct inode *inode, struct file *filp)
+{
+	struct flexcard_device *priv = filp->private_data;
+
+	filp->private_data = NULL;
+	kref_put(&priv->ref, flexcard_dev_release);
+
+	return 0;
+}
+
+static int flexcard_misc_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct flexcard_device *priv = filp->private_data;
+	unsigned long offset, vsize, psize, addr;
+
+	if (vma->vm_flags & (VM_WRITE | VM_EXEC))
+		return -EPERM;
+
+	offset = vma->vm_pgoff << PAGE_SHIFT;
+	vsize = vma->vm_end - vma->vm_start;
+	psize = pci_resource_len(priv->pdev, 0) - offset;
+	addr = (pci_resource_start(priv->pdev, 0) + offset) >> PAGE_SHIFT;
+
+	if (vsize > psize) {
+		dev_err(&priv->pdev->dev,
+			"requested mmap mapping too large\n");
+		return -EINVAL;
+	}
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+	return io_remap_pfn_range(vma, vma->vm_start, addr, vsize,
+				  vma->vm_page_prot);
+}
+
+static const struct file_operations flexcard_misc_fops = {
+	.owner		= THIS_MODULE,
+	.open		= flexcard_misc_open,
+	.release	= flexcard_misc_release,
+	.mmap		= flexcard_misc_mmap,
+	.llseek		= no_llseek,
+};
+
 static int flexcard_probe(struct pci_dev *pdev,
 			  const struct pci_device_id *id)
 {
 	struct flexcard_device *priv;
 	int ret;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
+	ret = ida_simple_get(&flexcard_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not get new Flexcard id:%d\n", ret);
+		goto out_free;
+	}
+
+	priv->cardnr = ret;
 	pci_set_drvdata(pdev, priv);
 	priv->pdev = pdev;
+	kref_init(&priv->ref);
+
+	snprintf(priv->name, sizeof(priv->name), "flexcard%d", priv->cardnr);
+	priv->dev.minor = MISC_DYNAMIC_MINOR;
+	priv->dev.name = priv->name;
+	priv->dev.fops = &flexcard_misc_fops;
+	priv->dev.parent = &pdev->dev;
 
 	ret = pci_enable_device(pdev);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to enable device: %d\n", ret);
-		return ret;
+		goto out_put;
 	}
 
 	pci_set_master(pdev);
@@ -143,6 +231,12 @@ static int flexcard_probe(struct pci_dev *pdev,
 		goto out_unmap;
 	}
 
+	ret = misc_register(&priv->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register miscdevice: %d\n", ret);
+		goto out_remove;
+	}
+
 	dev_info(&pdev->dev, "HW %02x.%02x.%02x FW %02x.%02x.%02x\n",
 		 priv->conf->fc_hw_ver.maj, priv->conf->fc_hw_ver.min,
 		 priv->conf->fc_hw_ver.dev, priv->conf->fc_fw_ver.maj,
@@ -150,12 +244,18 @@ static int flexcard_probe(struct pci_dev *pdev,
 
 	return 0;
 
+out_remove:
+	mfd_remove_devices(&pdev->dev);
 out_unmap:
 	iounmap(priv->conf);
 out_release:
 	pci_release_regions(pdev);
 out_disable:
 	pci_disable_device(pdev);
+out_put:
+	ida_simple_remove(&flexcard_ida, priv->cardnr);
+out_free:
+	kref_put(&priv->ref, flexcard_dev_release);
 
 	return ret;
 }
@@ -164,10 +264,13 @@ static void flexcard_remove(struct pci_dev *pdev)
 {
 	struct flexcard_device *priv = pci_get_drvdata(pdev);
 
+	misc_deregister(&priv->dev);
 	mfd_remove_devices(&pdev->dev);
 	iounmap(priv->conf);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
+	ida_simple_remove(&flexcard_ida, priv->cardnr);
+	kref_put(&priv->ref, flexcard_dev_release);
 }
 
 #define PCI_VENDOR_ID_EBEL	0x1974
diff --git a/include/linux/mfd/flexcard.h b/include/linux/mfd/flexcard.h
index 20d0f40..84e155c 100644
--- a/include/linux/mfd/flexcard.h
+++ b/include/linux/mfd/flexcard.h
@@ -19,11 +19,17 @@
 #define FLEXCARD_FR_OFFSET	0x4000
 #define FLEXCARD_FR_SIZE	0x2000
 
+#define FLEXCARD_MAX_NAME	16
+
 struct flexcard_device {
 	struct pci_dev *pdev;
 	struct fc_conf_bar __iomem *conf;
 	struct mfd_cell *cells;
 	struct resource *res;
+	struct miscdevice dev;
+	struct kref ref;
+	int cardnr;
+	char name[FLEXCARD_MAX_NAME];
 };
 
 enum flexcard_cell_id {
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 68ceb97..d5c5002 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -127,6 +127,7 @@ header-y += filter.h
 header-y += firewire-cdev.h
 header-y += firewire-constants.h
 header-y += flat.h
+header-y += flexcard.h
 header-y += fou.h
 header-y += fs.h
 header-y += fsl_hypervisor.h
-- 
2.1.4